Trilantic, which manages $7.3 billion worth of capital commitments, has a lease out for the full, 25,000-square-foot 39th floor at the top of Boston Properties’ swanky Park Avenue tower, sources told The Real Deal.

The asking rent for the space is $140 per square foot. Representatives for Trilantic and Boston Properties couldn’t be immediately reached for comment.

CBRE’s Peter Turchin, who is head of the leasing team on the building, declined to comment on the deal. But he did say the property is garnering lots of activity now that the $50 million renovation Boston Properties kicked off in 2016 is almost finished.

Boston Properties is overhauling the 1.7 million-square-foot tower between East 53rd and East 54th streets, which was built in 1961 as the headquarters of Citgroup. The landlord has been working to backfill some 385,000 square feet of vacancy left behind when Citigroup relocated to Tribeca.

Tricalantic’s deal is something of a homecoming for the company, which got its start nine years ago when five former Lehman Brothers executives bought the failed bank’s private-equity arm, Lehman Brothers Merchant Banking, out of bankruptcy.

LBMB, which was founded in 1986 as Lehman’s leveraged-buyout division, had been a tenant at 399 Park. When Trilantic took over, it signed a new, four-year lease in the building for a little more than 13,000 square feet.

Trilantic later relocated next door to RFR Realty’s Seagram Building at 375 Park Avenue, but now has its eye on the top of 399 Park, where the top floor has become available after investment advisor Cyrus Capital Partners signed a deal last year to relocate from Boston Properties’ building to Equity Office’s 65 East 55th Street. Jim Hanley of Hanley Advisors is representing Trilantic in negotiations. He declined to comment.

The Trilantic founders will see some familiar faces in the building.

Peterson Management, the investment firm that manages the family wealth of former Lehman CEO and Blackstone Group co-founder Peter Peterson, signed a 40,000-square-foot lease at the building last year.